Thin-Walled Structures最新文献

Shear performance prediction for corrugated steel web girders based on machine-learning algorithms 基于机器学习算法的波形钢腹板梁剪切性能预测

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-11-04 DOI: 10.1016/j.tws.2024.112668

This study aimed to predict the shear strength of corrugated steel web girders (CSWGs) by developing a new method based on four machine-learning (ML) algorithms, namely the support vector machine, artificial neural network, random forest, and XGBoost. Based on the acquired experimental and numerical data, a database containing 552 samples was constructed to train and test the ML models. A five-fold cross-validation approach was adopted during training to prevent model overfitting. A RandomizedSearchCV was used to optimize the hyperparameters of each model. The performance of the trained models was evaluated using four performance metrics, and the results revealed that the coefficients of determination (R²) of all ML models exceeded 0.97 when used on both training and validation sets, demonstrating the excellent performance of the ML models in predicting the shear strength of CSWGs. Additionally, the implemented ML models outperformed existing design codes and empirical formulae. The XGBoost model yielded the best prediction results with an R² of 0.999, mean absolute error of 44.98 kN, root-mean-square error of 66.67 kN, and mean absolute percentage error of 2.1 %. By using the Shapley additive explanation to derive a visual, quantitative explanation of the XGBoost model, the yield strength, web thickness, and web height were identified as the most critical factors affecting the shear strength of CSWGs, and their average absolute Shapley values accounted for approximately 91.45 % of the total value. The ML models implemented in this study provide a promising new approach for pre-designing and verifying the stability of CSWGs.

本研究旨在通过开发一种基于四种机器学习（ML）算法（即支持向量机、人工神经网络、随机森林和 XGBoost）的新方法来预测波形钢腹板梁（CSWG）的抗剪强度。根据获得的实验和数值数据，构建了一个包含 552 个样本的数据库，用于训练和测试 ML 模型。在训练过程中采用了五倍交叉验证方法，以防止模型过拟合。使用 RandomizedSearchCV 来优化每个模型的超参数。结果显示，所有 ML 模型在训练集和验证集上的决定系数（R2）都超过了 0.97，这表明 ML 模型在预测 CSWG 的剪切强度方面表现出色。此外，已实施的 ML 模型的性能优于现有的设计规范和经验公式。XGBoost 模型的预测结果最好，R2 为 0.999，平均绝对误差为 44.98 kN，均方根误差为 66.67 kN，平均绝对百分比误差为 2.1%。通过使用 Shapley 加法解释得出 XGBoost 模型的可视化定量解释，屈服强度、腹板厚度和腹板高度被确定为影响 CSWG 剪切强度的最关键因素，其平均绝对 Shapley 值约占总值的 91.45%。本研究采用的 ML 模型为预先设计和验证 CSWG 的稳定性提供了一种很有前途的新方法。

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引用次数: 0

An origami-wheeled robot with variable width and enhanced sand walking versatility 宽度可变的折纸轮式机器人，增强了沙地行走的多功能性

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-11-02 DOI: 10.1016/j.tws.2024.112645

Robots inspired by origami that offer several benefits, including being lightweight, requiring less assembly, and possessing remarkable deformability, have drawn a lot of interest. However, the existing origami-inspired robots are usually of limited functionalities and developing feature-rich robots is very challenging. Here, we report an origami-wheeled robot (OriWheelBot) with exceptional mobility for sand walking and a changing width. Origami wheels created using Miura origami permit the OriWheelBot to alter wheel width over obstacles. We derive the variable-width and diameter analytical models of the origami wheel, assuming rigid-folding, which has been confirmed by testing. An enhanced variant, dubbed iOriWheelBot, is additionally being developed to autonomously determine the obstacle's breadth. Based on the width of the channel between the barriers, three actions will be executed: direct pass, variable width pass, and direct return. Sand-pushing is more suitable for walking on the sand than sand-digging, which is the other of the two motion mechanisms that we have identified. Many aspects of sand walking, including carrying loads, walking on a slope, climbing a slope, and negotiating sand pits, small rocks, and sand traps, have been methodically investigated. The OriWheelBot can climb a 17-degree sand incline, vary its width by 40 %, and have a loading-carrying ratio of 66.7 % on flat sand. Rescue operations in disaster areas and planetary subsurface exploration can benefit from the OriWheelBot.

受折纸启发的机器人具有多种优点，包括重量轻、组装要求低、可变形性强等，因此备受关注。然而，现有的折纸启发机器人通常功能有限，开发功能丰富的机器人非常具有挑战性。在此，我们报告了一种折纸轮式机器人（OriWheelBot），它在沙地行走时具有超强的机动性，而且宽度可以改变。使用三浦折纸制作的折纸轮子允许 OriWheelBot 在遇到障碍物时改变轮子宽度。我们推导出折纸轮的可变宽度和直径分析模型，并假设其为刚性折叠，这一点已通过测试得到证实。此外，我们还开发了一种增强型机器人，被称为 iOriWheelBot，能够自主确定障碍物的宽度。根据障碍物之间通道的宽度，将执行三种操作：直接通过、变宽通过和直接返回。与我们确定的两种运动机制中的另一种--挖沙相比，推沙更适合在沙地上行走。我们已对沙地行走的许多方面进行了有条不紊的研究，包括承载负荷、在斜坡上行走、爬坡，以及在沙坑、小石头和沙坑中穿行。OriWheelBot可以爬上17度的沙坡，其宽度变化幅度为40%，在平坦的沙地上的负重率为66.7%。灾区救援行动和行星地下勘探都将受益于 OriWheelBot。

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引用次数: 0

Oscillating laser-arc hybrid additive manufacturing of aluminum alloy thin-wall based on synchronous wire-powder feeding 基于同步送丝送粉的铝合金薄壁振荡激光-电弧混合快速成型技术

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-11-02 DOI: 10.1016/j.tws.2024.112665

Synchronous wire-powder feeding was adopted to overcome the poor mechanical properties of aluminum alloy thin-wall caused by limited filling composition in wire-based laser-arc hybrid additive manufacturing. The results showed that the optimized Mg powder feeding improved the droplet transfer into a fine spray mode with reduced transition time by 18 %. Moreover, not only the effective width coefficient of thin-wall increased from 89 % to 95 %, but also the subsequent machining allowance reduced from 1.25 to 0.48 mm. The synchronous wire-powder feeding improved the formation accuracy by 61.6 %. Although the deposition microstructure was mainly composed of dendrites with obvious direction and increased average grain size by 54 %, a new Mg₂Si strengthened phase was also found. The ultimate tensile strength of thin-wall was increased by 12 % from 227.3 to 255.5 MPa. The related evolution mechanisms of deposition stability and mechanical properties by optimized powder feeding on the hybrid additive manufacturing were mainly discussed.

采用线材-粉末同步进给的方法克服了线材激光-电弧混合增材制造中由于填充成分有限而导致的铝合金薄壁力学性能差的问题。结果表明，优化的镁粉进给改善了液滴向精细喷雾模式的转移，过渡时间缩短了 18%。此外，不仅薄壁的有效宽度系数从 89% 提高到 95%，而且后续加工余量也从 1.25 mm 减少到 0.48 mm。线-粉同步进给使成形精度提高了 61.6%。虽然沉积微观结构主要由方向明显的树枝状晶组成，平均晶粒大小增加了 54%，但也发现了新的 Mg2Si 强化相。薄壁的极限抗拉强度从 227.3 兆帕提高到 255.5 兆帕，提高了 12%。主要讨论了优化粉末进料在混合快速成型过程中沉积稳定性和力学性能的相关演变机制。

引用次数: 0

Research on damage repair and high-velocity impact characteristics of thermoplastic composites 热塑性复合材料的损伤修复和高速冲击特性研究

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-11-01 DOI: 10.1016/j.tws.2024.112663

Low-velocity impact (LVI) can result in imperceptible damage to carbon fiber reinforced thermoplastic composites (CFRTP) laminates during service, leading to a reduction in structural strength. The thermal repair of damaged CFRTP laminates is conducted using the repairability of thermoplastic resin at high temperatures. However, the high-velocity impact characteristics of CFRTP laminates following thermal repair remain uncertain. This study examines CFRTP laminates made of two different materials (CF/PEEK and CF/PPS) with varying levels of low-velocity impact damage, and investigates the thermal repair process. A comparative experimental analysis examined the high-speed impact characteristics of CFRTP laminates under varying conditions. The results indicate that CF/PEEK laminates consistently exhibit superior compressive properties and impact resistance compared to CF/PPS laminates under similar conditions. Following damage from low-velocity impact, the compressive properties and high-velocity impact resistance of CFRTP laminates decrease, with CF/PPS laminates typically showing a lower performance retention rate. However, the thermal repair process proposed in this study significantly enhances the performance of CF/PPS laminates. Moreover, the degree of performance healing in CF/PPS laminates is consistently higher than that in CF/PEEK laminates, which is closely related to the semi-crystalline nature of PEEK resin.

在使用过程中，低速冲击（LVI）会对碳纤维增强热塑性复合材料（CFRTP）层压板造成难以察觉的损坏，导致结构强度降低。受损 CFRTP 层压板的热修复是利用热塑性树脂在高温下的可修复性进行的。然而，热修复后 CFRTP 层压板的高速冲击特性仍不确定。本研究考察了由两种不同材料（CF/PEEK 和 CF/PPS）制成的 CFRTP 层压板的不同低速冲击损伤程度，并研究了热修复过程。对比实验分析检验了 CFRTP 层压板在不同条件下的高速冲击特性。结果表明，在类似条件下，与 CF/PPS 层压板相比，CF/PEEK 层压板始终表现出更优越的抗压性能和抗冲击性能。低速冲击造成损坏后，CFRTP 层压板的压缩性能和高速冲击耐受性会下降，CF/PPS 层压板的性能保持率通常较低。然而，本研究提出的热修复工艺可显著提高 CF/PPS 层压材料的性能。此外，CF/PPS 层压板的性能修复程度始终高于 CF/PEEK 层压板，这与 PEEK 树脂的半结晶性质密切相关。

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引用次数: 0

Shear elastic buckling of corrugated steel plate shear walls with stiffeners considering torsional rigidity 考虑扭转刚度的带加强筋波纹钢板剪力墙的剪切弹性屈曲

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-31 DOI: 10.1016/j.tws.2024.112646

This paper conducted theoretical and numerical investigations on shear elastic buckling formulas of stiffened corrugated steel plate shear walls (SCSPSWs) considering torsional rigidities of stiffeners. Firstly, based on the orthotropic plate theory and the energy method, a theoretical model for the derivation of elastic buckling coefficients was established, introducing the torsional strain energy term of the stiffeners. On this basis, the variation law of the elastic buckling coefficient of the walls concerning the stiffener positions was studied, determining the optimal layout of the stiffeners. The formula for calculating the elastic buckling coefficient at any stiffener layout was provided. Furthermore, based on the stiffeners arranged in the optimal layout, the transition torsional rigidity of the stiffeners was determined, and the formulas for the elastic buckling coefficient of the SCSPSW with stiffeners considering torsional rigidity were proposed, in which the enhancement of torsional constraints provided by the stiffeners was measured by an enhancement factor. Finally, eigenvalue buckling analyses were performed based on finite element models to validate the theoretical analysis results on the optimal stiffener layout and elastic buckling coefficient.

本文对考虑加劲件扭转刚度的加劲波纹钢板剪力墙（SCSPSWs）的剪切弹性屈曲公式进行了理论和数值研究。首先，基于各向同性板理论和能量法，建立了推导弹性屈曲系数的理论模型，引入了加劲件的扭转应变能项。在此基础上，研究了墙体弹性屈曲系数随加劲件位置的变化规律，确定了加劲件的最佳布局。提供了在任何加强筋布局下的弹性屈曲系数计算公式。此外，根据加劲件的最佳布局，确定了加劲件的过渡扭转刚度，并提出了考虑扭转刚度的带加劲件 SCSPSW 的弹性屈曲系数公式，其中加劲件提供的扭转约束的增强用增强系数来衡量。最后，基于有限元模型进行了特征值屈曲分析，以验证关于最佳加劲件布局和弹性屈曲系数的理论分析结果。

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引用次数: 0

Experimental and numerical investigation on cyclic behavior of Q1100 ultra-high strength steel H-section compressive-bending members about strong-axis Q1100 超高强度钢 H 型截面强轴受压弯曲构件循环行为的实验和数值研究

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-30 DOI: 10.1016/j.tws.2024.112651

Q1100 refers to ultra-high strength steel (UHSS) with a nominal yield strength of 1100 MPa. Hysteretic tests were conducted on seven Q1100 UHSS H-section welded columns to assess their hysteretic performance. The hysteretic performance was evaluated through hysteresis curves, damage phenomena, energy dissipation, ductility, and load-carrying capacity. The impact of the width-to-thickness ratio and axial pressure ratio on the hysteretic behavior was also investigated. A validated finite element model was utilized to analyze the hysteresis behavior, influencing factors, and the applicability of Eurocode 3 width-to-thickness ratio limits, resulting in proposed seismic design recommendations.

Q1100 是指名义屈服强度为 1100 兆帕的超高强度钢 (UHSS)。对七根 Q1100 超高强度钢 H 型焊接柱进行了滞回试验，以评估其滞回性能。通过滞后曲线、损伤现象、能量耗散、延展性和承载能力对滞后性能进行了评估。此外，还研究了宽厚比和轴压比对滞回行为的影响。利用经过验证的有限元模型分析了滞后行为、影响因素以及 Eurocode 3 宽厚比限制的适用性，从而提出了抗震设计建议。

引用次数: 0

A rationalized macroscopic failure criterion of composite woven fabrics for airship structures 用于飞艇结构的复合编织物的合理化宏观失效标准

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-29 DOI: 10.1016/j.tws.2024.112647

Composite woven fabrics are increasingly employed in architecture and aerospace for their excellent properties, such as lightweight, high specific strength, large surface area, and satisfactory deployability. The strength behavior is essential for various membrane structures as structural failure is serious. However, an accurate, simplified, and universal failure criterion has not been reported due to the inherent complexities of composite woven fabrics. This paper thus studies the tensile strength behaviors of airship fabrics and proposes a rationalized macroscopic failure criterion (Chen-Chen criterion) based on theoretical analysis and experimental observations. The generalized Chen-Chen criterion inherently satisfies the conditions of symmetry, dimensionless, and uniaxial tensile strength (UTS) boundary, with a maximum absolute deviation of only 1.34 % for two airship fabrics. Additionally, the UTS-based criteria were derived particularly for flexible plain-weave polyesters to avoid laborious and costly biaxial strength tests. The average deviations of constant and linear Chen-Chen criteria are 6.01 %, 4.91 %, while that of the Norris criterion reaches 13.34 %. Furthermore, the numerical implementation of the Chen-Chen criterion was demonstrated by biaxial tensile simulations. The failure strength and location predicted by the numerical analysis show good consistency with the experimental results.

复合编织物具有重量轻、比强度高、比表面积大、可展开性好等优良特性，因此越来越多地应用于建筑和航空航天领域。强度行为对各种膜结构至关重要，因为结构失效是非常严重的。然而，由于复合编织物固有的复杂性，准确、简化和通用的失效标准尚未见报道。因此，本文在理论分析和实验观察的基础上，研究了飞艇织物的拉伸强度行为，并提出了合理化的宏观失效准则（Chen-Chen 准则）。广义的 Chen-Chen 判据本质上满足对称、无量纲和单轴抗拉强度（UTS）边界条件，两种飞艇织物的最大绝对偏差仅为 1.34%。此外，基于 UTS 的标准特别适用于柔性平纹聚酯，以避免费力且昂贵的双轴强度测试。恒定和线性 Chen-Chen 准则的平均偏差分别为 6.01 % 和 4.91 %，而 Norris 准则的平均偏差则达到 13.34 %。此外，双轴拉伸模拟也证明了 Chen-Chen 准则的数值实施。数值分析预测的破坏强度和破坏位置与实验结果显示出良好的一致性。

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引用次数: 0

Test and simulation of high temperature resistant polyamide composite with single lap single bolt connection 采用单搭接单螺栓连接的耐高温聚酰胺复合材料的测试与模拟

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-29 DOI: 10.1016/j.tws.2024.112649

The advancement of next-generation aerospace vehicles has presented new requirements and challenges for ensuring the structural integrity of aircraft components in extreme environments. Consequently, the utilization of high temperature resistant polyamide composite materials has become pivotal in the manufacturing of aerospace vehicle parts that operate under high temperatures (250 °C). As a critical connection technology for these materials, the mechanical behavior of bolted connection structures under high temperatures requires further investigation. In this paper, a combination of experimental and numerical simulation is used to investigate the load carrying capacity and failure mechanism of T700/BMP316 composite bolted joints at room temperature and 250 °C. The experimental results show that the ultimate load carrying capacity of the structure at 250 °C is only 13.1 % lower than that of the room temperature environment, indicating that the temperature softening effect of such composites is not significant. Scanning electron microscope (SEM) and computed tomography (CT) results indicate that the structural damage modes were the crushing of the hole edge fibers and matrix due to the extrusion by the bolts, as well as the interlaminar delamination damage. Temperature effects were taken into account for the composite principal structure and finite element modeling was performed using a combination of Pinho criterion and Cohesive model. Numerical simulations allow accurate prediction of the load-displacement response and damage pattern throughout the damage evolution phase. The high temperature test results and the developed finite element model involved in this study can support the design of new-generation aerospace vehicles.

新一代航空航天飞行器的发展为确保极端环境下飞行器部件的结构完整性提出了新的要求和挑战。因此，使用耐高温聚酰胺复合材料已成为制造在高温（250 °C）下工作的航空航天飞行器部件的关键。作为这些材料的关键连接技术，螺栓连接结构在高温下的机械性能需要进一步研究。本文采用实验和数值模拟相结合的方法，研究了 T700/BMP316 复合材料螺栓连接在室温和 250 ℃ 下的承载能力和失效机理。实验结果表明，该结构在 250 °C 时的极限承载能力仅比室温环境下低 13.1%，表明此类复合材料的温度软化效应并不显著。扫描电子显微镜（SEM）和计算机断层扫描（CT）结果表明，结构的破坏模式是螺栓挤压造成的孔边纤维和基体挤压，以及层间分层破坏。复合材料主体结构考虑了温度效应，并结合使用了 Pinho 准则和 Cohesive 模型进行了有限元建模。通过数值模拟，可以准确预测整个损伤演变阶段的载荷-位移响应和损伤模式。本研究中涉及的高温试验结果和开发的有限元模型可为新一代航空航天飞行器的设计提供支持。

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引用次数: 0

Stretch-induced wrinkling analysis and experimental validation of creased membranes 皱褶膜的拉伸诱发皱褶分析和实验验证

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-29 DOI: 10.1016/j.tws.2024.112644

Creases and wrinkles are crucial factors affecting the accuracy of membrane structures. In this paper, we study the stretch-induced wrinkling of creased membrane based on a proposed planar crease model by characterizing the crease as an orthotropic rigid strip with effective bending stiffness and initial stress. A control equation of wrinkling of a stretched rectangular membrane with a vertical crease is deduced to understand the crease-wrinkle interaction. Then, a set of scaling laws for the wrinkles is discussed in detail, and it is concluded that the ratio of the bending stiffness of the crease to that of the membrane is the key influence factor. Furthermore, the analysis reveals that wrinkling in the small-strain stage is a localized wrinkling behavior independent of the crease parameters. The wrinkling wavelength and amplitude at large strains decrease with increasing crease angle. Finally, experiments verify the correctness and validity of the theoretical model and analytical method.

折痕和褶皱是影响膜结构精度的关键因素。本文基于提出的平面折痕模型，将折痕表征为具有有效弯曲刚度和初始应力的正交刚性条带，研究了拉伸引起的折痕膜起皱。推导出带有垂直折痕的拉伸矩形膜起皱的控制方程，以理解折痕与起皱的相互作用。然后，详细讨论了皱褶的一组缩放定律，并得出结论：皱褶的弯曲刚度与膜的弯曲刚度之比是关键的影响因素。此外，分析表明，小应变阶段的起皱是一种局部起皱行为，与折痕参数无关。大应变时的起皱波长和振幅随着折痕角度的增大而减小。最后，实验验证了理论模型和分析方法的正确性和有效性。

引用次数: 0

Enhanced energy absorption and mechanical properties of porous Ti-6Al-4 V alloys with gradient disordered cells fabricated by laser powder bed fusion 通过激光粉末床熔融技术制造具有梯度无序晶胞的多孔 Ti-6Al-4 V 合金，增强其能量吸收和机械性能

IF 5.7 1区工程技术 Q1 ENGINEERING, CIVIL

Thin-Walled Structures

Pub Date : 2024-10-28 DOI: 10.1016/j.tws.2024.112632

Additive manufacturing (AM) has revolutionized the production of porous metals, greatly improving control over their structural properties and offering unprecedented advantages in lightweight applications and energy absorption. Balancing energy absorption and compressive strength in ordered and disordered porous structures is challenging due to shear deformation and deformation mechanisms. This study investigates the mechanical and energy absorption properties of porous Ti-6Al-4 V alloys with gradient disordered cells fabricated using laser powder bed fusion (LPBF). The compressive response of samples with different regularities (R) and varying layers of disordered cells was analyzed through quasi-static compression experiments and finite element simulations. The results indicate that introducing a disordered cell gradient significantly enhances energy absorption by preventing the formation of shear bands observed in porous structures with ordered cell structures. When the regularity (R) is 0.8, 0.4, and 0.2 with one or two layers of disordered cells, mechanical properties are optimized and characterized by a balance between compressive strength and energy absorption. It is significant that, while preserving or enhancing compressive strength, the energy absorption of the material can be augmented substantially. Specifically, porous Ti-6Al-4 V (R = 0.8, L4) achieves an energy absorption increase of up to 154.9kJ/m³, which represents a dramatic enhancement of approximately 245.0 % over the regular porous structure (R = 0 or L0), which absorbs only 44.9 kJ/m³. Compared to ordered and disordered porous structures, the disordered cell gradient demonstrates significant potential in tuning the mechanical properties of porous metals, thereby advancing their applications in aerospace, biomedical, and protective fields.

增材制造（AM）彻底改变了多孔金属的生产，极大地改善了对其结构特性的控制，并在轻质应用和能量吸收方面提供了前所未有的优势。由于剪切变形和变形机制的原因，在有序和无序多孔结构中平衡能量吸收和抗压强度具有挑战性。本研究探讨了使用激光粉末床熔融（LPBF）制造的具有梯度无序单元的多孔 Ti-6Al-4 V 合金的机械和能量吸收特性。通过准静态压缩实验和有限元模拟，分析了具有不同规则性（R）和不同无序晶胞层的样品的压缩响应。结果表明，引入无序细胞梯度可以防止在具有有序细胞结构的多孔结构中观察到的剪切带的形成，从而显著增强能量吸收。当规则度（R）分别为 0.8、0.4 和 0.2 且有一层或两层无序细胞时，机械性能得到了优化，其特点是抗压强度和能量吸收之间达到了平衡。重要的是，在保持或增强抗压强度的同时，材料的能量吸收能力也能得到大幅提高。具体来说，多孔 Ti-6Al-4 V（R = 0.8，L4）的能量吸收率最高可达 154.9kJ/m³，与普通多孔结构（R = 0 或 L0）相比，能量吸收率大幅提高了约 245.0%，普通多孔结构的能量吸收率仅为 44.9 kJ/m³。与有序和无序多孔结构相比，无序细胞梯度在调整多孔金属的机械性能方面具有巨大潜力，从而推动了它们在航空航天、生物医学和防护领域的应用。

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引用次数: 0